| Background and Objective: Radiotherapy is very important in treating tumors. About 70 % malignant tumors need radiotherapy in China, and 60% in US by statistics in 1983. But radiotherapy has no good response for some patients, the main reason is that the 10%- 50 % of hypoxic cells in solid tumors have low response to radiotherapy. In solid malignant tumors, abnormal structure and function of vessels bring about decreased supply of oxygen to tumor, malignant tumor consume a large quantity of oxygen because it grows and metabolizes quickly, so malignant tumor is often in hypoxic condition. The more hypoxic the condition is, the less radiosensitive the tumor is. So exploring the hypoxic extent of tumor cells can predict the effects of radiotherapy and help medical doctors to choose the best therapy strategy. It can improve the successful rate of radiotherapy. Recently, some scholars attach more importance to research of hypoxic agents, such as 99mTc-HL91, a great number of animal experiments and preliminary clinical observation indicated that the imaging ability of 99mTc-HL91 is superior to other hypoxic agents. It manifested higher radioactivity rations of hypoxic to normal tissues, and has no cytotoxicity. It is a new hypoxic agent which has great exploratory prospect.The aim of the study is to explore the value of 99mTc-HL91 imaging inpredicting the radiosensibility of tumors by comparing the imaging of glioma patients with their effects of radiotherapy.Methods: Thirty patients with untreated glioma underwent Tc-HL91 plannar imagings at 10min, 2h, and 4h postinjection of 99mTc-HL91. Low energy high resolution collimator was used, energy peak was 140KeV, window width was 10%, Zoom was 1.0-2.0.The tumor -to-normal ratio (T/N) was calculated by drawing ROI. After examination, the patients accepted radiotherapy, 4 weeks later, the efeects of radiotherapy were evaluated under the helps of the radiotherapistsaccording to the standard of WHO. Then the value of 99mTc-HL91 imaging in predicting the radiosensibility of tumors was evaluated.Results: 1 )Thirty 99mTc-HL91 glioma imagings, which early T/N average value was 1.453 + 0.292, medium one was 1.532+0.299,late one was 1.607+ 0.305, had significant difference between every two phases.2) Among thirty glioma patients, there is no case of complete remission(CR) ; there are 15cases of partial remission(PR); 6 cases of no changing (NC);there is one case of progressive depravation (PD), and there are 8 cases of death and no follow-up. The groups of effective radiotherapy (CR+PR) and ineffective radiotherapy (NC+PD), which the T/N average value of early phase were 1.333 + 0.277 and 1.779 + 0.183 respectively, had significant difference (P=0.001, 2 tails); The medium T/N average value of the two groups were 1.409 + 0.274 and 1.856 + 0.185 respectively, there was significant difference between the two groups (P=0.001, 2 tails); The late T/N average value of the two groups were 1.484 + 0.278 and 1.937 + 0.191 respectively, there was significant difference between the two groups .(P=0.001, 2tails)3) After injection of 99mTc-HL91, no adverse or subjective side effects were noticed in any of the subjects.4) Significant radioactivity was shown in nose and oropharynx of all of the patients.Conclusions:1) To brain tumor, early 99mTc-HL91 imaging can manifest, but from early to late imaging, the T/N values are gradually increasing.The statistical results show significant difference between the T/N values of every two phases. There is low background in late imaging,so high quality image can be acquired.2) 99mTc-HL91 brain tumor imaging can explore hypoxic extent of tumor cells, thus can be used to predict the radiosensibility of brain tumors, which can help doctors to choose the best therapy strategy and improve the successful rate of radiotherapy.3) There is no adverse or subjective side effects of 99mTc-HL91.4) 99mTc-HL91 imaging has less clinical usefulness for the patients with nasal and oral tumor.
|
PDF Full Text Request